The present invention is directed to a flange protector and masking device for use with a flange which may be used, for instance, for making connections to pipes, valves, etc. Such flanges have bolt holes adapted to receive bolts for making such connections to a mating flange having corresponding bolt holes.
The flange face surface will typically be finely machined to ensure a tight seal between the mating flange surfaces and an intervening sealing gasket that is compressed between the opposing flange surfaces when connected together with bolts via the bolt holes in the opposing flanges. As operating pressures in the piping systems where flanges are used can exceed 2,500 PSI, any type of damage to the flange sealing surface (nicks, scratches, dings, etc.) can create significant maintenance and safety issues. The use of a flange protector during storage, shipment, etc. is thus found useful to protect the flange face surface as a cost avoidance to expensive field repairs and/or replacement.
It is also desirable to mask the raised flange surface when painting or otherwise preparing the surface of the flange. A device to accomplish such a result is deemed very useful in the industry.
A number of flange protector designs are known. See, for instance, U.S. Pat. Nos. 1,903,220; 2,708,453; 3,563,277; 3,856,050; 3,942,681; 4,014,368; 4,233,697; 4,423,753; 4,915,137; 5,265,752; 5,503,189; 5,435,350; 5,546,989; 6,332,478; and 6,532,992.
A number of products are commercially available, including self-adhesive die-cut raised face protectors, push-in flange protectors which engage the central bore of the flange and cover the entire flange, lid-like flange covers which snap into place over the entire flange in locking engagement with the flange rim, die-cut flange covers which may be bolted into place onto the flange by means of holes in the flange cover, and flange protectors which have lugs which fit into the bolt holes of the flange to hold the flange cover into place.
While generally satisfactory, such designs are in need of improvement. For instance, it is at times difficult to install the flange protector, particularly when the flange protector has lugs which must be seated within bolt holes spaced about the periphery of a flange to be protected. Depending upon the flexibility of the flange protector body, it may be difficult to engage a number of lugs within multiple bolt holes at the same time.
The use of adhesives may be less than effective due to the potential effect of the environment during storage and transport. The use of bolts to attach the die-cut flange protector is labor intensive from the standpoint of attachment and removal. The use of whole-flange covers requires the use of a multitude of sizes, and such covers are ineffective as masking devices.
Additionally, injection molded designs typically contain molded-in stresses, and warping frequently prevents the protector from laying flat against the raised sealing face of the valve or flange. This condition creates gaps between the protector and the raised face making the surface more prone to damage, and additionally making installation and removal more difficult.
It may also be difficult to remove the flange protector once installed on the flange when lugs are used, as the flange protector is maintained in place by the action of multiple lugs which are each snugly fit within a bolt hole. The removal of the lugs is made more difficult due to the fact that a number of lugs must be removed at the same time, as well as the fact that the lugs must each be lifted from the bolt holes in the direction of the longitudinal axis of the bolt holes in order to be removed. Such removal is also made difficult by the fact that the flange protector is relatively inflexible, since the material employed must be impact-resistant in order to provide adequate protection. The fact that the bolt holes are spaced differently for different types of flanges also necessitates the use of flange covers of differing dimensions having lugs spaced differently to accommodate different bolt hole spacing.
It is, however, recognized that, irrespective of the spacing of the bolt holes, the diameter of the flange face does not differ for a particular class of flange irrespective of the diameter of the flange itself, and the differing spacing dimensions for the bolt holes. This provides an advantage in that the protection of the flange face itself may be focused upon while ignoring the varied bolt hole spacings if the flange protector can be attached to the flange without resorting to use of the bolt holes as anchoring means.
It is accordingly an object of the present invention to provide a flange protector and masking device suitable for protective engagement with the raised face of a flange, which flange protector and masking device may both be easily installed on the raised face of the flange, as well as easily removed yet reusable, while still providing satisfactory protection for the raised face of the flange during storage and/or transport, without resort to the use of bolt holes as an anchoring mechanism.
The retention feature of the flange protector and masking device of the present invention additionally is quite different from other prior art used where the protector skirt is used for both protection of the raised face and also retention through an interference fit (hoop stress) along the outside skirt of the protector.
Finally, the present invention provides significant cost advantages over other prior art because of the elegance of the design, simplified tooling, low cost tooling for plastic injection molding, and material usage only where absolutely needed for raised face protection. Other designs require full flange coverage, or coverage beyond the raised face area for retention and/or the use of multiple components for attachment and securing the protector to the flange.
Yet another advantage of the present invention is that the protector can additionally be used as a masking device to mask off the raised flange face during sand blasting, painting, and or plating of the valve or fitting.